Over the past 30 years, the ability to treat respiratory problems in adults and infants has significantly improved. As newer developments enter the field, a greater number of smaller and more immature infants are able to be treated for respiratory problems.
Notwithstanding its increased use, the overall success of treating respiratory insufficiency is limited by the inherent problems of conventional ventilator support systems. For example, over 20% of those who require prolonged mechanical ventilation often develop chronic respiratory problems such as airway injury and dysfunction as seen in bronchopulmonary dysplasia (henceforth "BPD").
Although some controversy exists concerning the pathogenesis of BPD in the neonate, many believe that prolonged mechanical ventilation is one of the major factors resulting therein. Serial assessment of pulmonary function during the first year of life in infants surviving hyaline membrane disease and developing BPD have concluded that the duration and pressures of mechanical ventilation damaged the airways and lungs; thus, interfering with their growth. Within this context, greater assisted ventilatory requirements (e.g., pressure and duration) of the very premature infant relative to the older infant precipitate an age-related predisposition for pulmonary damage and BPD. In addition, those patients who acquire BPD continue to have respiratory support problems which are similar to patents with a chronic obstructive pulmonary disease (henceforth "COPD"). Such diseases often require the implementation of supplemental oxygen. Moreover, due to lung dysfunction, there is also a great expenditure of energy associated therewith (e.g., elevated resistance, poor diffusion of gas, etc.).
It is known in the industry, that gas exchange and cardiovascular stability may be maintained in patients with lung disease by ventilating them with a mixture of helium and oxygen (henceforth "heliox"). When being ventilated with a heliox mixture, a patient's airway and pulmonary resistances are decreased. This results in a decrease in the work of breathing and/or a reduction in the pressure effort required for breathing. In addition, such mechanical effects on the lungs, coupled with improved gas diffusion, can be of benefit to patients with many different types of lung disease.
Despite the extensive collection of physiological data with experimentally developed components known in the art, to the Applicants' knowledge no one has ever reported a heliox-based ventilation system which includes, among other things, a complex interactive control process facilitated by a servo-control unit in order to maintain gas exchange, optimize lung function, minimize ventilation pressures, and maintain cardiovascular stability and temperature.
As would be expected, due to frequent changes in the physiological needs of patients during conventional heliox ventilation procedures, patients who are subjected to such procedures are monitored to determine whether there is a need to make adjustments. However, since it is labor and cost intensive to continuously monitor such patients, their status is typically monitored only periodically.
Since the need for making adjustments often occurs between the periodic status checks, these patients are frequently subjected to less than optimal ventilation conditions for varying periods of time. Depending upon the setting(s) which need(s) to be adjusted, and upon the time period over which the patient is subjected to the less than optimal ventilation condition(s), the resulting consequences can be catastrophic and even fatal.
Although medical practitioners appreciate the ways in which heliox ventilation procedures can aid them in the treatment of patients, they are, never-the-less, hesitant of subjecting patients thereto since there is little known as to how such procedures can be safely implemented and optimized. For example, practitioners are aware that, if not properly implemented, a patient being ventilated with a heliox blend of gases can experience any of the following conditions within only a few breathing cycles: overdistention of the lungs, air way collapse, incomplete diffusion of gases to and from the patient, and the like. Moreover, if these conditions are permitted to continue for a few minutes, the patient can experience brain damage, suffocation, stroke, blindness and even death.
Notwithstanding the possible complications which can result when subjecting patients to heliox ventilation procedures, medical practitioners are still attempting to implement these procedures in more and more clinical applications due to the significant advantages associated therewith. Accordingly, there is presently an immediate need for a means for safely implementing and optimizing heliox ventilation procedures.
To date, amidst all of today's sophisticated technology and the tens of thousands of highly skilled professionals in the medical industry and profession, no such means exists. Rather, the possibility of complications materializing during a conventional heliox ventilation procedure rests largely upon the personal skill and knowledge of the specific practitioner implementing the procedure and the physiological strength and stability of the patient.